Physical channel configuration signaling procedures

ABSTRACT

A sequence of codes are provided for potential assignment to a user in a wireless hybrid time division multiple access (TDMA)/code division multiple access (CDMA) communication system. At least one timeslot is selected to support the communication. For each selected timeslot, at least one code is selected. If more than one code is selected, the selected codes are consecutive in the provided codes sequence. For at least one of the selected timeslots, an identifier of a first and last code of the selected consecutive codes is signaled. The user receives the signaled identifier and uses the selected consecutive codes, as identified, to support the communication.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/145,371 filed May 14, 2002, which is a continuation of U.S. patentapplication Ser. No. 10/029,651 filed Dec. 21, 2001, which claims thebenefit of U.S. Provisional Patent Application No. 60/290,717 filed May14, 2001, which are incorporated by reference as if fully set forth.

BACKGROUND

The invention is generally related to wireless hybrid time divisionmultiple access (TDMA)/code division multiple access (CDMA)communication systems. In particular, the invention relates toconfiguring physical channels in such systems.

Wireless communication systems are evolving from carrying primarilyvoice and paging information to carrying voice, paging and other datainformation, such as wireless Internet data. The bandwidth required forall these types of information varies greatly. Some of this datarequires far more bandwidth than traditional voice and paginginformation.

In CDMA communication systems, multiple communications are sent in ashared spectrum. These communications are distinguished by theirchannelization codes. To more efficiently use the shared spectrum,hybrid TDMA/CDMA communication systems time divide the shared bandwidthinto repeating frames having a specified number of timeslots. Acommunication is sent in such a system using one or multiple timeslotsand one or multiple codes. One such system is the universal mobiletelecommunication systems (UMTS) time division duplex (TDD)communication system using CDMA, which uses fifteen (15) timeslots. InTDD, a particular cell's timeslot is used only for either uplink ordownlink communications.

To deal with the variety of bandwidths required for variouscommunications, adaptive modulation and coding (AM&C) is used. In AM&C,the modulation and coding scheme for transmitting data is varied to moreefficiently use the radio resources. To illustrate, the modulation usedfor data may be varied, such as using binary phase shift keying (BPSK),quadrature phase shift keying (QPSK), or M-ary quadrature amplitudemodulation. Furthermore, the data may be assigned a single code in atimeslot, multiple codes in a timeslot, a single code in multipletimeslots or multiple codes in multiple timeslots.

Since data transmitted to or from particular user equipment (UE) may besent with a variety of modulation, timeslot and coding schemes, thismodulation/timeslot/coding information must be conveyed to the UE. Thistype of information is typically signaled or broadcast to a UE and istypically performed using a low speed control channel. Signaling thisinformation uses valuable overhead and air resources. Since AM&C istypically not applied to control channels, any information sent over acontrol channel uses much more air resources than would be required ifthe information was sent over a channel to which AM&C is applied.However, reducing signaling overhead is desirable regardless of whetheror not AM&C is used.

Accordingly, it is desirable to transmit as much of themodulation/timeslot/coding information as possible over channels towhich AM&C is applied. Additionally, it is desirable to reduce timeslotand code assignment signaling.

SUMMARY

A sequence of codes are provided for potential assignment to a user in awireless hybrid TDMA/CDMA communication system. At least one (1)timeslot is selected to support the communication. For each selectedtimeslot, at least one (1) code is selected. If more than one code isselected, the codes are selected consecutively. For at least one (1) ofthe selected timeslots, an identifier of a first and last code of theselected consecutive codes is signaled. The user receives the signaledidentifier and uses the selected consecutive codes, as identified, tosupport the communication.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified illustration of wireless physical channelconfiguration signaling system for the downlink.

FIG. 2 is a simplified illustration of such a system for the uplink.

FIG. 3 is a flow diagram for signaling using consecutive codes.

FIG. 4 is a table illustrating assigning using consecutive codes.

FIG. 5 is a flow diagram for signaling using common consecutive codes.

FIG. 6 is a table illustrating assigning using common consecutive codes.

FIG. 7 is a flow diagram for signaling using common consecutive codes inconsecutive timeslots.

FIG. 8 is a table illustrating assigning using common consecutive codesin consecutive timeslots.

FIG. 9 is a flow diagram for signaling using entire timeslotassignments.

FIG. 10 is a table illustrating entire timeslot assignments.

FIG. 11 is a flow diagram for signaling using consecutive entiretimeslots.

FIG. 12 is a table illustrating consecutive entire timeslot assignments.

FIG. 13 is a table summarizing the bits required to signal thecode/timeslot assignments for a sixteen code and twelve availabletimeslot system.

FIG. 14 is a flow diagram for the method of numbering all codesconsecutively in all timeslots.

FIG. 15 is a table illustrating consecutive code assignment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described with reference to the drawingfigures wherein like numerals represent like elements throughout.

One method 53 for assigning codes to timeslots in accordance with thepresent invention uses consecutive codes and will be described withreference to the flow diagram of FIG. 3, and a simplified illustrationof such code assignments for UE A, UE B and UE C is shown in FIG. 4. InFIG. 4, twelve (12) potential timeslots and sixteen (16) potential codesare shown, although the present invention is not limited to a specificnumber of timeslots and/or codes.

Each timeslot is potentially assigned a predetermined number of codes,such as sixteen codes. The predetermined number of codes are assigned anorder or sequence, such as from 0 to 15, (step 54). For a particular UE,only consecutive codes are assigned to that UE in a given timeslot,(step 56). To illustrate, referring to FIG. 4 for UE A in timeslot 2,codes 4-8 are assigned. An assignment of codes 1, 3 and 4 to UE A is notpermitted, unless code 2 is also assigned to UE A. Likewise, UE A intimeslot 6 has been assigned codes 6-9; UE B in timeslot 2 has beenassigned codes 9-12 and in timeslot 9 has been assigned codes 0-13; andUE C in timeslot 11 has been assigned codes 1-5.

Referring back to FIG. 3, to signal this assignment scheme to a UE, foreach assigned timeslot, an indication of the first code and the lastcode of the consecutive codes is required, (step 58). For a sixteen (16)potential code sequence, eight (8) bits are required. Four (4) bitsindicate the start code, (code 0 to 15), and four (4) bits indicate thelast code or the number of consecutive codes, (code 0 to 15) or thenumber (1 to 16) of consecutive codes. For a twelve (12) timeslotsystem, 96 bits are needed, (eight (8) bits per timeslot by twelve (12)timeslots).

One approach to reduce the number of bits signaled for downlinktransmissions in the control channels is to signal only a small portionof the assignment information over a control channel, (hereinafterreferred to as “prior signaled information” ), and signal the remainingportion of the assignment information with the downlink data,(hereinafter referred to as “post signaled information”). The postsignaled information sent with the downlink data will undergo the sameAM&C processing as the data, thereby significantly reducing the amountof air resources required to transmit the assignment information overthe control channel.

In a typical system, it takes two (2) timeslots to recover the data,since the control information must be received and then processed inorder to be ready to receive the actual data. The prior signaledinformation must therefore only relay the assignment information for thefirst two (2) timeslots used to transmit downlink data which comprises afour (4) bit indicator for the first used timeslot; a four (4) bitindicator for the next timeslot; and indicators, (two (2) bits each),for the first and last codes for each of the used timeslots.Accordingly, only a maximum of sixteen (16) bits are signaled as priorsignaled information. The remaining assignment information is signaledas post signaled information with the downlink data. As a result, for asixteen (16) code and a twelve (12) timeslot system, only sixteen (16)bits are prior signaled information, with the remaining post signaledinformation signaled with the downlink data.

One advantage to this approach is that it allows the use of any numberof codes in any timeslot. However, this approach requires signaling fortypically at least two timeslot assignments, and possibly all timeslotassignments. Although this limits the code choice to consecutive codes,with the use of code reassignment, this restriction is not significant.If an optimal reassignment requires non-consecutive codes, the timeslotUE code usage can be repacked to allow the assignment of onlyconsecutive codes to all UEs.

A second method 80 to assign codes and timeslots uses common consecutivecodes and is described with reference to the flow diagram of FIG. 5 andthe simplified illustration of such code assignments for UE A, UE B andUE C in FIG. 6. Each timeslot is potentially assigned a predeterminednumber of codes, such as sixteen (16) codes. The predetermined number ofcodes are assigned an order or sequence, such as from 0 to 15, (step82). The same set of consecutive codes assigned to one timeslot must beassigned to all timeslots used for a particular UE, (step 84). Toillustrate using FIG. 6, UE A is assigned timeslots 2, 3 and 11 and isassigned codes 2-4 in each timeslot. However, since UE A was assignedcodes 2-4 in timeslot 2, it could not be assigned only code 2 or codes2-5 in another timeslot. Likewise, UE B is assigned codes 0-13 intimeslots 8 and 9; and UE C is assigned code 11 in timeslots 11 and 12.

To signal this assignment scheme to a UE, an indication of the first andlast codes of the consecutive codes is required as well as an indicatorof the used timeslots (step 86). For the system of FIG. 6, eight (8)bits are required for the consecutive codes, (four (4) bits for thefirst code and four (4) bits for the last code or number of codes), andtwelve (12) bits to identify the used timeslot(s). Each bit correspondsto a timeslot. In one (1) implementation, a one (1) bit value indicatesthat the timeslot is used and a zero (0) bit value indicates that it isnot used. Thus, a total of twenty (20) bits are required.

The use of prior signaled information and post signaled information withthis method 80 reduces the number of prior signaled bits. The priorsignaled information must indicate the first used timeslot and thefollowing timeslot, and the first and last codes of the common sequence.For the system of FIG. 6, eight (8) bits indicating the first two (2)timeslots of the twelve (12) timeslots, (four (4) bits to indicate eachtimeslot) and eight (8) bits for the start and end codes or number ofcodes. Thus, a total of sixteen (16) bits of prior signaled informationis required.

To further reduce the bits of the prior signaled information, five (5)bits may be used for the first two (2) timeslots. Four (4) bitsindicates the first used timeslot and the fifth bit represents whetherthe following timeslot is used. As a result, either sixteen (16) orthirteen (13) bits are prior signaled information, with at most ten (10)bits of post signaled information.

One advantage to the second method is that it reduces the amount ofprior signaled information. One drawback is that it reduces flexibilityin code and timeslot assignments, since each timeslot used by aparticular UE must be assigned the same codes.

A third method 90 for code and timeslot assignment uses commonconsecutive codes in consecutive timeslots and is described withreference to the flow diagram of FIG. 7 and the simplified illustrationof such code assignments for UE A, UE B and UE C in FIG. 8. Eachtimeslot is potentially assigned a predetermined number of codes, suchas sixteen (16) codes. The predetermined number of codes are assigned anorder or sequence, such as from 0 to 15, (step 92). In this approach,not only are the same codes assigned for each used timeslot, but alsoonly consecutive timeslots may be assigned, (step 94). To illustrateusing FIG. 8, UE A is assigned codes 2-4 in timeslots 5-7. However, UE Acould not be assigned codes 2-4 in timeslots 5, 6 and 8, unless timeslot7 was also assigned. Likewise, UE B is assigned codes 0-13 in timeslots8 and 9. UE B could not be assigned a lesser or greater number of codesin any other timeslots, nor could it be assigned codes 0-13 in timeslot11 or 12, unless timeslot 10 was also assigned. UE C is assigned code 11in timeslot 11.

To signal this assignment scheme to a UE, an indication of the first andlast (or number of) assigned codes in each assigned timeslot and anindication of the first and last (or number of) assigned timeslots,(step 96). For the system of FIG. 8, eight (8) bits are required for thecode assignments and eight (8) bits for the timeslot assignments, (four(4) for the first timeslot and four (4) for the last, or number of,timeslots), totaling sixteen (16) bits.

The use of prior signaled information and post signaled information withthis method 90 reduces the number of prior signaled bits. In this method90, thirteen (13) bits must to be signaled prior to the data, (eight (8)for the codes used in the timeslots, four (4) for the first usedtimeslot and one (1) bit to indicate whether another timeslot is used).If another timeslot is used, four (4) bits indicating the last, ornumber of, timeslots are signaled as post signaled information with thedata.

This third method limits the amount of signaling, but at the expense ofcode/timeslot assignment flexibility.

A fourth method 100 to assign codes and timeslots assigns UEs all thecodes in a timeslot and is described with reference to the flow diagramof FIG. 9 and the simplified illustration of such code assignments forUE A, UE B and UE C in FIG. 10. In this approach, the UEs are assignedall of the codes in a timeslot (step 102). To illustrate using FIG. 10,UE A is assigned all the codes of timeslots 2 and 5, UE B is assignedall of the codes of slots 8 and 9, and UE C is assigned all of the codesof timeslot 11.

To signal this assignment scheme to a UE, an indicator of the assignedtimeslots is needed, (step 104). For the system of FIG. 10, theindicator is a twelve (12) bit field, with each bit representing whethera particular timeslot is used. Typically, the maximum number of codes ina timeslot is known by the UE. However, if the maximum number of codesis not known, an indicator of the number of codes is sent, (also a partof step 104), such as four (4) bits indicating a maximum number of codesranging from 0 to 16.

The use of prior signaled information and post signaled information withthis method 100 reduces the number of prior signaled bits. In thismethod 100, an indicator of the first two used timeslots is signaled.For the system of FIG. 10, this two timeslot indicator is eight (8)bits. The indicator of the remaining assigned timeslots is signaled aspost signaled information with the data in the first timeslot.Alternately, to further reduce the number of signaled bits, five (5)bits of prior signaled information may be used. Four (4) bits indicatethe first timeslot and the fifth bit indicates whether the followingtimeslot is used.

A fifth method 110 for code and timeslot assignment uses entireconsecutive timeslots and is described with reference to the flow chartof FIG. 11 and the simplified illustration of such assignments for UE A,UE B and UE C in FIG. 12. In this approach, a UE is assigned all of thecodes in consecutive timeslots (step 112). To illustrate using FIG. 12,UE A is assigned all the codes of timeslots 2-4. UE A could not beassigned all the codes of timeslots 2, 3 and 5 without also assigning UEA timeslot 4. Likewise, UE B is assigned all of the codes of timeslots 8and 9; and UE C all of the codes of timeslot 11.

To signal this assignment scheme to a UE, an indicator of the first andlast timeslots (or number of) used timeslots is signaled, (step 114).For the system of FIG. 11, eight (8) bits are required, (four (4) forthe first used timeslot and four (4) for the last or number oftimeslots).

The use of prior signaled information and post signaled information withthis method 110 reduces the number of prior signaled bits. In thismethod 110, only five (5) bits are sent as prior signaled information.Four (4) bits indicate the first used code and the fifth bit indicateswhether the following timeslot is used. If the following timeslot isused, four (4) bits are signaled as post signaled information with thetransmitted downlink data to indicate the last timeslot or number oftimeslots.

A sixth method 120 numbers all codes consecutively in all timeslots andis described with reference to the flow diagram of FIG. 14 in thesimplified illustration of such codes assignments for UEA, UEB and UECin FIG. 15. In this method 120, all of the codes are numberedconsecutively in all timeslots (step 122). The UE is then assigned adesired number of codes (step 124). To illustrate using FIG. 15, UEA isassigned codes 69-99, UEB is assigned codes 129-142 and UEC is assignedcodes 162-181.

To signal this assignment scheme to a UE, an indicator of the first andlast codes is needed (step 126). For the system of FIG. 15, theindicator is sixteen (16) bits, (eight (8) bits for the first codes andeight (8) bits for the last code). Alternatively, the indicator of thefirst code may be signaled along with the number of codes; particularlywhen the number of codes is small.

The use of prior signaled information and post signaled information withthis method 120 reduces the number of prior signaled bits. In thismethod 120, thirteen (13) bits must be signaled as prior signaledinformation, (eight (8) for the first code and five (5) bits for thenumber of codes in the first two (2) timeslots). If more codes are used,the code count can be superceded in the post signaled information.

The table of FIG. 13 summarizes the bits required to signal thecode/timeslot assignment for the six (6) schemes for a sixteen (16) codeand twelve (12) available timeslot system.

Although the present invention may be implemented by many physicalsystems, one such system for implementing the invention will bedescribed with reference to FIG. 1. FIG. 1 illustrates a simplifiedwireless hybrid TDMA/CDMA communication system for use in physicalchannel configuration signaling. A preferred implementation is fordownlink transmitted data, such as for a high speed downlink channel,although physical channel configuration signaling may also be used inother implementations, such as the uplink.

Downlink data to be communicated to a particular UE 24 is assigned atleast one code and at least one timeslot by a resource management device28. The resource management device 28 may be in a radio networkcontroller (RNC) or Node-B 20. The resource management device 28 assignscodes and timeslots as will be described in detail hereinafter. Theassigned code and timeslot are sent to a signaling transmitter 30 and anAM&C controller 32 in the base station 22. The signaling transmitter 30formats for transmission the code and timeslot information as will alsobe described in detail hereinafter.

A data modulation and spreading device 34 modulates, spreads and timemultiplexes the downlink data in the timeslots and with the codesassigned by the resource management device 28. The modulated data andsignaled information is radiated by an antenna 36 or antenna arraythrough a wireless radio channel 26.

At the particular UE 24, the transmitted downlink data and signaledinformation is received by an antenna 38. A signaling receiver 40recovers the signaled information and relays it to an AM&C controller42. The AM&C controller 42 determines the modulation to be used andindicates the code and timeslot used for the downlink data to the datadetection device 44. One potential data detection device 44 is a jointdetection device using a channel estimation device, although other datadetection devices may be used. The data detection device 44 recovers thedownlink data using the timeslot and code information from the AM&Ccontroller 42.

FIG. 2 illustrates a simplified system for use in uplink physicalchannel configuration signaling. The resource management device 28assigns the code/timeslot to be used for the particular UE's uplinkdata. The assigned code/timeslot are sent to a signaling transmitter 30in the base station 22. The signaling transmitter 30 formats fortransmission the code and timeslot information as will be described indetail hereinafter. The signaled information is passed through a switch48 or isolator and radiated by an antenna 36 or antenna array through awireless radio channel 26.

The particular UE 24 receives the signaled information. The receivedinformation is passed thorough a switch 50 or isolator to a signalingreceiver 40. The signaled information is recovered by the signalingreceiver 40 and relayed to an AM&C controller 42. The AM&C controller 42relays the uplink code and timeslot assignment to the data modulationand spreading device 52. The data modulation and spreading device 52modulates, spreads and time multiplexes the uplink data as directed bythe AM&C controller 42 in the timeslots and with codes signaled by thebase station 22. The modulated data is passed through a switch 50 orisolator and radiated by the UE antenna 38 through the wireless radiochannel 26.

The transmitted data is received by the base station antenna 36 orantenna array. The received data is passed through a switch 48 orisolator to a data detection device 46. One possible data detectiondevice 46 is a joint detection device using a channel estimation device,although other data detection devices may be used. A base station AM&Ccontroller 32 receives the code and timeslot assignment from theresource management device 28. The data detection device 46 recovers theuplink data from the received uplink signal using the assigned code andtimeslot as directed by the AM&C controller 32.

While the present invention has been described in terms of the preferredembodiment, other variations which are within the scope of the inventionas outlined in the claims below will be apparent to those skilled in theart.

1. A method for signaling code and timeslot assignments to support acommunication of a user in a wireless hybrid time division multipleaccess (TDMA)/code division multiple access (CDMA) communication systemcomprising at least one transmitter and at least one receiver, wherebythe system supports wireless RF communications utilizing at least onetimeslot from a predetermined sequence of timeslots and at least onecode from a predetermined sequence of codes, the method comprising: atthe transmitter: selecting a plurality of timeslots; for said pluralityof selected timeslots, selecting consecutive codes from saidpredetermined sequence, wherein each selected timeslot is assigned asame set of consecutive codes; and signaling an identifier whichidentifies said plurality of timeslots, a first code of said consecutivecodes, and a last code of said consecutive codes, wherein the identifierfor each timeslot is a bit with a bit value of one indicating that thetimeslot is used for the communication and a bit value of zeroindicating that the timeslot is not used for the communication; and atthe receiver: receiving the signaled identifier; and using theidentified timeslots and the identified consecutive codes to support thecommunication.
 2. The method of claim 1 wherein the communication is adownlink communication.
 3. The method of claim 1 wherein the hybridTDMA/CDMA communication system is a hybrid time division duplexcommunication system using CDMA.
 4. A wireless hybrid time divisionmultiple access (TDMA)/code division multiple access (CDMA) transmitterfor signaling code and timeslot assignments to support an RFcommunication utilizing at least one timeslot from a predeterminedsequence of timeslots and at least one code from a predeterminedsequence of codes, comprising: a selector for selecting a plurality oftimeslots, and for said plurality of timeslots, selecting consecutivecodes from said predetermined sequence, wherein each selected timeslotis assigned a same set of consecutive codes; a signaler for signaling anidentifier which identifies said plurality of timeslots, a first code ofsaid consecutive codes, and a last code of said consecutive codes,wherein the identifier for each timeslot is a bit with a bit value ofone indicating that the timeslot is used for the communication and a bitvalue of zero indicating that the timeslot is not used for thecommunication; whereby the transmitter uses said timeslots and saididentified codes to support the RF communication.
 5. The transmitter ofclaim 4 wherein the communication is a downlink communication.